Please join us at the 2011 Energy, Utility & Environment Conference Jan 31-Feb 2 in Phoenix AZ where we will present:
Lessons from Forty Plant-Months of “Co-Benefit” Mercury Abatement Using Existing Pollutant Control Equipment, J. O. Allen, M. Brandon Looney, and C. A. Tyree.
Production data from five baseload coal-fired power plants were analyzed in order to evaluate the effectiveness of existing pollution control equipment for the control mercury emissions. The existing processes are selective catalytic reduction (SCR), electrostatic precipitiation (ESP), and wet flue gas desulphurization (wFGD). More than forty plant-months of process and emissions data were collected into a large data set. Mercury emissions were calculated in lb/TBtu using EPA methods. Mercury control efficiencies were 90% or greater on 47% of the study days. Lower collection efficiencies were observed when 1) load was near capacity, 2) boilers started up, 3) SCR units were off-line, and 4) mercury was re-emitted from FGD liquor. These results are consistent with mercury oxidation in SCR units and elsewhere, followed by collection and sequestration of oxidized mercury in FGD liquor. Mercury control data for periods with full load, NOx control, and SO2 control were analyzed assuming normal and log-normal distributions. The prediced 99% upper predicted performance means using the assumed distributions were significantly lower than the actual 99th percentile mercury emissions. We will discuss the implications of these findings for the upcoming EPA mercury MACT rule.